// SPDX-License-Identifier: MIT /* * Copyright © 2023-2024 Intel Corporation */ #include #include "xe_assert.h" #include "xe_device.h" #include "xe_gt_sriov_printk.h" #include "xe_gt_sriov_vf.h" #include "xe_pm.h" #include "xe_sriov.h" #include "xe_sriov_printk.h" #include "xe_sriov_vf.h" /** * DOC: VF restore procedure in PF KMD and VF KMD * * Restoring previously saved state of a VF is one of core features of * SR-IOV. All major VM Management applications allow saving and restoring * the VM state, and doing that to a VM which uses SRIOV VF as one of * the accessible devices requires support from KMD on both PF and VF side. * VMM initiates all required operations through VFIO module, which then * translates them into PF KMD calls. This description will focus on these * calls, leaving out the module which initiates these steps (VFIO). * * In order to start the restore procedure, GuC needs to keep the VF in * proper state. The PF driver can ensure GuC set it to VF_READY state * by provisioning the VF, which in turn can be done after Function Level * Reset of said VF (or after it was freshly created - in that case FLR * is not needed). The FLR procedure ends with GuC sending message * `GUC_PF_NOTIFY_VF_FLR_DONE`, and then provisioning data is sent to GuC. * After the provisioning is completed, the VF needs to be paused, and * at that point the actual restore can begin. * * During VF Restore, state of several resources is restored. These may * include local memory content (system memory is restored by VMM itself), * values of MMIO registers, stateless compression metadata and others. * The final resource which also needs restoring is state of the VF * submission maintained within GuC. For that, `GUC_PF_OPCODE_VF_RESTORE` * message is used, with reference to the state blob to be consumed by * GuC. * * Next, when VFIO is asked to set the VM into running state, the PF driver * sends `GUC_PF_TRIGGER_VF_RESUME` to GuC. When sent after restore, this * changes VF state within GuC to `VF_RESFIX_BLOCKED` rather than the * usual `VF_RUNNING`. At this point GuC triggers an interrupt to inform * the VF KMD within the VM that it was migrated. * * As soon as Virtual GPU of the VM starts, the VF driver within receives * the MIGRATED interrupt and schedules post-migration recovery worker. * That worker queries GuC for new provisioning (using MMIO communication), * and applies fixups to any non-virtualized resources used by the VF. * * When the VF driver is ready to continue operation on the newly connected * hardware, it sends `VF2GUC_NOTIFY_RESFIX_DONE` which causes it to * enter the long awaited `VF_RUNNING` state, and therefore start handling * CTB messages and scheduling workloads from the VF:: * * PF GuC VF * [ ] | | * [ ] PF2GUC_VF_CONTROL(pause) | | * [ ]---------------------------> [ ] | * [ ] [ ] GuC sets new VF state to | * [ ] [ ]------- VF_READY_PAUSED | * [ ] [ ] | | * [ ] [ ] <----- | * [ ] success [ ] | * [ ] <---------------------------[ ] | * [ ] | | * [ ] PF loads resources from the | | * [ ]------- saved image supplied | | * [ ] | | | * [ ] <----- | | * [ ] | | * [ ] GUC_PF_OPCODE_VF_RESTORE | | * [ ]---------------------------> [ ] | * [ ] [ ] GuC loads contexts and CTB | * [ ] [ ]------- state from image | * [ ] [ ] | | * [ ] [ ] <----- | * [ ] [ ] | * [ ] [ ] GuC sets new VF state to | * [ ] [ ]------- VF_RESFIX_PAUSED | * [ ] [ ] | | * [ ] success [ ] <----- | * [ ] <---------------------------[ ] | * [ ] | | * [ ] GUC_PF_TRIGGER_VF_RESUME | | * [ ]---------------------------> [ ] | * [ ] [ ] GuC sets new VF state to | * [ ] [ ]------- VF_RESFIX_BLOCKED | * [ ] [ ] | | * [ ] [ ] <----- | * [ ] [ ] | * [ ] [ ] GUC_INTR_SW_INT_0 | * [ ] success [ ]---------------------------> [ ] * [ ] <---------------------------[ ] [ ] * | | VF2GUC_QUERY_SINGLE_KLV [ ] * | [ ] <---------------------------[ ] * | [ ] [ ] * | [ ] new VF provisioning [ ] * | [ ]---------------------------> [ ] * | | [ ] * | | VF driver applies post [ ] * | | migration fixups -------[ ] * | | | [ ] * | | -----> [ ] * | | [ ] * | | VF2GUC_NOTIFY_RESFIX_DONE [ ] * | [ ] <---------------------------[ ] * | [ ] [ ] * | [ ] GuC sets new VF state to [ ] * | [ ]------- VF_RUNNING [ ] * | [ ] | [ ] * | [ ] <----- [ ] * | [ ] success [ ] * | [ ]---------------------------> [ ] * | | | * | | | */ static void migration_worker_func(struct work_struct *w); /** * xe_sriov_vf_init_early - Initialize SR-IOV VF specific data. * @xe: the &xe_device to initialize */ void xe_sriov_vf_init_early(struct xe_device *xe) { INIT_WORK(&xe->sriov.vf.migration.worker, migration_worker_func); } /** * vf_post_migration_requery_guc - Re-query GuC for current VF provisioning. * @xe: the &xe_device struct instance * * After migration, we need to re-query all VF configuration to make sure * they match previous provisioning. Note that most of VF provisioning * shall be the same, except GGTT range, since GGTT is not virtualized per-VF. * * Returns: 0 if the operation completed successfully, or a negative error * code otherwise. */ static int vf_post_migration_requery_guc(struct xe_device *xe) { struct xe_gt *gt; unsigned int id; int err, ret = 0; for_each_gt(gt, xe, id) { err = xe_gt_sriov_vf_query_config(gt); ret = ret ?: err; } return ret; } /* * vf_post_migration_imminent - Check if post-restore recovery is coming. * @xe: the &xe_device struct instance * * Return: True if migration recovery worker will soon be running. Any worker currently * executing does not affect the result. */ static bool vf_post_migration_imminent(struct xe_device *xe) { return xe->sriov.vf.migration.gt_flags != 0 || work_pending(&xe->sriov.vf.migration.worker); } /* * Notify all GuCs about resource fixups apply finished. */ static void vf_post_migration_notify_resfix_done(struct xe_device *xe) { struct xe_gt *gt; unsigned int id; for_each_gt(gt, xe, id) { if (vf_post_migration_imminent(xe)) goto skip; xe_gt_sriov_vf_notify_resfix_done(gt); } return; skip: drm_dbg(&xe->drm, "another recovery imminent, skipping notifications\n"); } static void vf_post_migration_recovery(struct xe_device *xe) { int err; drm_dbg(&xe->drm, "migration recovery in progress\n"); xe_pm_runtime_get(xe); err = vf_post_migration_requery_guc(xe); if (vf_post_migration_imminent(xe)) goto defer; if (unlikely(err)) goto fail; /* FIXME: add the recovery steps */ vf_post_migration_notify_resfix_done(xe); xe_pm_runtime_put(xe); drm_notice(&xe->drm, "migration recovery ended\n"); return; defer: xe_pm_runtime_put(xe); drm_dbg(&xe->drm, "migration recovery deferred\n"); return; fail: xe_pm_runtime_put(xe); drm_err(&xe->drm, "migration recovery failed (%pe)\n", ERR_PTR(err)); xe_device_declare_wedged(xe); } static void migration_worker_func(struct work_struct *w) { struct xe_device *xe = container_of(w, struct xe_device, sriov.vf.migration.worker); vf_post_migration_recovery(xe); } static bool vf_ready_to_recovery_on_all_gts(struct xe_device *xe) { struct xe_gt *gt; unsigned int id; for_each_gt(gt, xe, id) { if (!test_bit(id, &xe->sriov.vf.migration.gt_flags)) { xe_gt_sriov_dbg_verbose(gt, "still not ready to recover\n"); return false; } } return true; } /** * xe_sriov_vf_start_migration_recovery - Start VF migration recovery. * @xe: the &xe_device to start recovery on * * This function shall be called only by VF. */ void xe_sriov_vf_start_migration_recovery(struct xe_device *xe) { bool started; xe_assert(xe, IS_SRIOV_VF(xe)); if (!vf_ready_to_recovery_on_all_gts(xe)) return; WRITE_ONCE(xe->sriov.vf.migration.gt_flags, 0); /* Ensure other threads see that no flags are set now. */ smp_mb(); started = queue_work(xe->sriov.wq, &xe->sriov.vf.migration.worker); drm_info(&xe->drm, "VF migration recovery %s\n", started ? "scheduled" : "already in progress"); }